Support for Half / bfloat16 / index_select and better testing (#53898)
Summary:
Added the support for half / bfloat / bool for `index_select`, as suggested by ngimel in
https://github.com/pytorch/pytorch/issues/49707#issuecomment-788140578
For the tests to pass, I also added the support for `index_add`.
I added `OpInfo` tests for `index_add` and more thorough forward tests for `index_select` to test these changes.
While doing so, I found that the support for scalar types in the derivative of `index_add` was not correct, so I corrected it.
Resolves https://github.com/pytorch/pytorch/issues/49707
It should also resolve similar issues that I encountered when porting `index_copy`, `take` and `put`.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/53898
Reviewed By: mruberry
Differential Revision: D27193294
Pulled By: ngimel
fbshipit-source-id: 5a0af2c62a0cf24f3cc9c74f230ab4f3712bbb7a
